The subject of the invention is an equipment for the excavation of trees by disrooting them and a process for taking down the trees by this way.
Basically there are two types of processes for lumbering, i.e. separation of the bole from the root-trunk, and the assart. In the first case the root-trunk being remained in the earth after chopping down the bole is regularly extracted separately by forked pushing tools or tines mounted on a tractor (using considerable large stroke) or e.g. by blasting. According to the current methods grubs can be used as well. One type of them drills into the root-trunk and slices or splinters it. The other type drills around the root-trunk with a sharp cylinder, cuts the roots and finally excavates the root-trunk.
In case of assart the separation of the bole from the earth is done below the terrain level. If the root-trunk should also be excavated being as a more favourable solution regularly this method is used. Both types of lumbering have advantages and disadvantages. Positive character of the assart is that the quantity of the wood increases, complete soil preparation and re-trenching can be carried out afterwards, the falling tree suffers less damage, and no effort should be made to excavate the root-trunk. The assart can be carried out either manually or by machine. In the first case the rootage is digged out then cut just at the root-trunk toward the falling direction. This accident-prone work is considerably slow. Regarding the machine-made solutions drawing and expelling methods are known. In the former case a throwing double-wheel is fastened vertically to the timber (the timber is felled on it) and the rope of the pulley tackle is fastened at a certain (calculated) height to the timber as well. By the pulling power of the pulley tackle the timber is taken down then the approaching by the double-wheel can be done too. Disadvantage of the method is that due to the high pulling power very often the timber breaks.
According to the expelling method the timber is turned out by lifting the root-trunk with the blade or fork of a power machine being mounted with a felling-frame, felling-beetle and a lifting fork while in the meantime the bole is pushed ahead. In this case very often the problem is that during the holding process of the root-trunk the tool gets clogged and consequently it is not able to carry out the process or considerable high pressing force is needed. (University of Forestry and Timber Industry, textbook of Forestry Engineering faculty, Dr Rumpf J{dot over (a)}nos: Erdöhasználattan I. 1986, Sopron)
Patent specification No. CH 674.118 discusses an equipment mounted to the hydraulic system of a conventional machine (e.g. tractor), which in a nearly vertical position “rips out” the tree together with its roots from the earth. By the application of an equipment mounted with arms for holding the timber it takes the bole and its hydraulic cylinders apply an upward force. In the meantime an eccentric disc is actuated from the machine which forces the units of the system and the timber into an alternative movement. According to the authors it makes the process easier, which is true, nevertheless this solution is applicable economically only in cases of smaller trees. Further disadvantage is that the timber holding arms may vertically slip causing difficulties in the process.
Patent application No. WO 93/04575 discusses an equipment mounted on a machine and consisting of an abutting arm and a V-shaped dipper-cultivating tool being attached to it, which is used for felling trees with their root-trunks. Disadvantage of the equipment is that sometimes it gets clogged and does not provide proper grabbing.